La citadelle de Brouage et la dynamique paléoenvironnementale du marais charentais: l’apport de la malacologie et palynologie

International audienceL'ancien port de Brouage est situé face à l'île d'Oléron, aujourd'hui en plein marais, à quelques kilomètres de la mer. Si le chenal est aujourd'hui inaccessible à tout bateau de fort tonnage, cela n'a pas été le cas à l'époque moderne. La fouille de la maison Champlain, initiée dès 2003 par K. Robin (Conseil Général de la Charente-Maritime) et reprise depuis par A. Champagne, a donc la particularité de se situer dans un milieu humide dont la géomorphologie et la dynamique sédimentaire ont considérablement fluctué. La compréhension de ces évolutions est au cœur de nos préoccupations au niveau à la fois de l'implantation de cette citadelle en zone littorale mais aussi de la gestion des ressources alimentaires et matériaux de construction. La prospection géophysique entreprise en 2010 par V. Mathé, a été confrontée à des données géotechniques anciennes (Mathé 2010). Elle a précisé l'hypothèse d'une ville établie sur un banc de sable, reposant sur du bri, et non sur un banc de galets de lest. Les différentes phases de terrain avaient permis de reconnaître ces sables sur lesquels les diverses structures anthropiques s'installent

La citadelle de Brouage et la dynamique paléoenvironnementale du marais charentais: l’apport de la malacologie et palynologie

International audienceL'ancien port de Brouage est situé face à l'île d'Oléron, aujourd'hui en plein marais, à quelques kilomètres de la mer. Si le chenal est aujourd'hui inaccessible à tout bateau de fort tonnage, cela n'a pas été le cas à l'époque moderne. La fouille de la maison Champlain, initiée dès 2003 par K. Robin (Conseil Général de la Charente-Maritime) et reprise depuis par A. Champagne, a donc la particularité de se situer dans un milieu humide dont la géomorphologie et la dynamique sédimentaire ont considérablement fluctué. La compréhension de ces évolutions est au cœur de nos préoccupations au niveau à la fois de l'implantation de cette citadelle en zone littorale mais aussi de la gestion des ressources alimentaires et matériaux de construction. La prospection géophysique entreprise en 2010 par V. Mathé, a été confrontée à des données géotechniques anciennes (Mathé 2010). Elle a précisé l'hypothèse d'une ville établie sur un banc de sable, reposant sur du bri, et non sur un banc de galets de lest. Les différentes phases de terrain avaient permis de reconnaître ces sables sur lesquels les diverses structures anthropiques s'installent

AT1 Receptor Mediated Hypertensive Response to Ang II in the Nucleus Tractus Solitarii of Normotensive Rats Involves NO Dependent Local GABA Release

AimIt is well-established that angiotensin II exerts a dampening effect on the baroreflex within the nucleus tractus solitarii (NTS), the principal brainstem site for termination of baroreceptor afferents and which is densely populated with gamma-aminobutyric acid (GABA)ergic neurons and nerve terminals. The present study was designed to investigate whether local release of GABA is involved in the effects mediated by local angiotensin II within the NTS.MethodsIn vivo microdialysis was used for measurement of extracellular glutamate and GABA levels and for infusion of angiotensin II within the NTS of conscious normotensive Wistar rats. The mean arterial pressure (MAP) and heart rate response to local infusion of angiotensin II were subsequently monitored with a pressure transducer under anesthesia. The angiotensin II type 1 receptor (AT1R) antagonist, candesartan, was used to assess whether responses were AT1R dependent and the nitric oxide (NO) synthase inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), was used to assess the involvement of NO in the evoked responses by infusion of angiotensin II. The MAP and heart rate responses were monitored with a pressure transducer.ResultsLocal infusion into the NTS of angiotensin II induced a significant to ninefold significantly increase in extracellular GABA levels; as well as MAP was increased by 15 mmHg. These responses were both abolished by co-infusion of either, the angiotensin II type 1 receptor antagonist, candesartan, or the NO synthase inhibitor, L-NAME, demonstrating that the effect is not only AT1R dependent but also NO dependent. The pressor response to angiotensin II was reversed by co-infusion with the GABAA receptor antagonist, bicuculline. Local blockade of NO synthase decreased both, GABA and glutamate concentrations.ConclusionOur results suggest that the AT1R mediated hypertensive response to angiotensin II within the NTS in normotensive rats is GABA and NO dependent. Nitric oxide produced within the NTS tonically potentiates local GABA and glutamate release

Efficient CPP-mediated Cre protein delivery to developing and adult CNS tissues

<p>Abstract</p> <p>Background</p> <p>Understanding and manipulating gene function in physiological conditions is a major objective for both fundamental and applied research. In contrast to other experimental settings, which use either purely genetic or gene delivery (viral or non-viral) strategies, we report here a strategy based on direct protein delivery to central nervous system (CNS) tissues. We fused Cre recombinase with cell-penetrating peptides and analyzed the intracellular biological activity of the resulting chimerical proteins when delivered into cells endowed with Cre-mediated reporter gene expression.</p> <p>Results</p> <p>We show that active Cre enzymatic conjugates are readily internalized and exert their enzymatic activity in the nucleus of adherent cultured cells. We then evaluated this strategy in organotypic cultures of neural tissue explants derived from reporter mice carrying reporter "floxed" alleles. The efficacy of two protocols was compared on explants, either by direct addition of an overlying drop of protein conjugate or by implantation of conjugate-coated beads. In both cases, delivery of Cre recombinase resulted in genomic recombination that, with the bead protocol, was restricted to discrete areas of embryonic and adult neural tissues. Furthermore, delivery to adult brain tissue resulted in the transduction of mature postmitotic populations of neurons.</p> <p>Conclusion</p> <p>We provide tools for the spatially restricted genetic modification of cells in explant culture. This strategy allows to study lineage, migration, differentiation and death of neural cells. As a proof-of-concept applied to CNS tissue, direct delivery of Cre recombinase enabled the selective elimination of an interneuron subpopulation of the spinal cord, thereby providing a model to study early events of neurodegenerative processes. Thus our work opens new perspectives for both fundamental and applied cell targeting protocols using proteic cargoes which need to retain full bioactivity upon internalisation, as illustrated here with the oligomeric Cre recombinase.</p

Revisiting Out-of-SSA Translation for Correctness, Code Quality, and Efficiency

Compared to the previous versions, the only change is correcting an awful typo that made Algorithm 1 wrong. Line 18 is not "if b = loc(pred(b))" but simply "if b = loc(b)".Static single assignment (SSA) form is an intermediate program representation in which many code optimizations can be performed with fast and easy-to-implement algorithms. However, some of these optimizations create situations where the SSA variables arising from the same original variable now have overlapping live ranges. This complicates the translation out of SSA code into standard code. There are three issues to consider: correctness, code quality (elimination of copies), and algorithm efficiency (speed and memory footprint). Briggs et al. proposed patches to correct the initial approach of Cytron et al. A cleaner and more general approach was proposed by Sreedhar et al., along with techniques to reduce the number of generated copies. We propose a new approach based on coalescing and a precise view of interferences, in which correctness and optimizations are separated. Our approach is provably correct and simpler to implement, with no patches or particular cases as in previous solutions, while reducing the number of generated copies. Also, experiments with SPEC CINT2000 show that it is 2x faster and 10x less memory-consuming than the Method~III of Sreedhar et al., which makes it suitable for just-in-time compilation

Hypotensive Response to Angiotensin II Type 2 Receptor Stimulation in the Rostral Ventrolateral Medulla Requires Functional GABA-A Receptors

Objectives: Angiotensin II, glutamate and gamma-aminobutyric acid (GABA) interact within the rostral ventrolateral medulla (RVLM) and the paraventricular nucleus (PVN) modulating the central regulation of blood pressure and sympathetic tone. Our aim was to assess the effects of local angiotensin II type 2 receptor stimulation within the RVLM and the PVN on neurotransmitter concentrations and mean arterial pressure (MAP).Methods:In vivo microdialysis was used for measurement of extracellular glutamate and GABA levels and for local infusion of the angiotensin II type 2 receptor agonist Compound 21 in the RVLM and the PVN of conscious normotensive Wistar rats. The MAP response to local Compound 21 was monitored with a pressure transducer under anaesthesia. Angiotensin II type 2 receptor selectivity was assessed using the angiotensin II type 2 receptor antagonist PD123319; the GABA-A receptor antagonist bicuculline was used to assess the involvement of GABA-A receptors.Results: Infusion of Compound 21 (0.05 μg/μl/h) in the RVLM significantly increased GABA levels and lowered blood pressure. These effects were abolished by co-infusion with PD123319. No changes in neurotransmitter levels or effects on blood pressure were seen with PD123319 infusion alone. Co-infusion of bicuculline abolished the Compound 21 evoked decrease in MAP. Infusion of Compound 21 within the PVN did not change extracellular neurotransmitter levels nor MAP.Conclusion: Selective stimulation of angiotensin II type 2 receptor within the RVLM by local Compound 21 infusion reduces blood pressure and increases local GABA levels in normotensive rats. This hypotensive response requires functional GABA-A receptors, suggesting that GABAergic neurons are involved in the sympatho-inhibitory action underlying this hypotensive response

Liquid crystal micro-cells for tunable VCSELs

International audienceWe recently demonstrated the tunability of a VCSEL with an intra-cavity liquid crystal layer. This demonstration was made on a macroscopic-sized sample with optical pumping. For a further development of this solution, it is necessary to place the liquid crystal on microscopic VCSEL chips. We developed a microtechnology process which makes it possible to fabricate liquid crystal micro-cells in a collective process